Westminster Presbyterian in Dubuque’s Outdoor Lighting Improvement


Upgrade older parking lot and exterior light fixtures to LED lighting fixtures. This is a quick, uncomplicated project to reduce lighting energy requirements by at least 70% while it also reduces light pollution and detrimental insect attraction.

Westminster Presbyterian Church in Dubuque, Iowa, has two separate parking lots with wide two-way driveways and about 100 parking spaces. The parking areas were illuminated by 8 incandescent light fixtures mounted on four poles that were installed 20 years ago. In addition, two lights were mounted on the building to light the front and rear entrances. In 2019, the annual cost for the parking lot lighting alone was about $1200 – about 10 percent of the total electrical utility expense.

In 2019, the eight incandescent lights on four poles were replaced with four 143-watt, 15,000-lumen LED fixtures fitted with optical lenses that more evenly distribute light over the parking lot and reduce the light projected at neighbors. The two building lights were replaced with 9,000-lumen LED lights. The total installed cost was just under $4000. The lights have 5-year warranties and are rated at a lumen loss of around 10% after 50,000 hours.

The replacement was simple. The old fixtures were removed from the poles and building and the new fixtures were connected to existing wires and remounted. The parking lot lights are on a separate meter. We can directly verify that, with the $600 rebate from the electrical utility and subsequent electrical cost increases, the payback is under three years.


  • The photo shows the installer moving into position to remove two old fixtures (they appear just above the lift boom) that were on top of each pole.
  • All six lights are on timers that turn on at dusk and turn off at midnight. This has worked well for us for decades.
  • Motion sensors for each light were an available option. Although this could have reduced electrical use further and provided a security alert, our supplier was concerned about the more frequent cycling reducing LED and control life. Check this feature out. It seems likely that concern about reduced life may be lower after two additional years of technology advances.
  • LED parking area lights are equipped with engineered optical lenses that control light much more evenly and efficiently than the previous bulb lights did with their metal reflectors. Consequently, light is directed only downward and to where it is wanted.
  • Replacement of the lights avoided costly servicing to replace bulbs every 5 years. Also, after 20 years, the electronic ballasts were beginning to fail.
  • Light pollution is an increasing concern, especially because it attracts and confuses insects and detrimentally affects their life. A study by the University of Bristol (UK) confirms the expectation that LED lights attract fewer insects because LED lights have lower levels of insect-attracting ultraviolet light compared to incandescent and fluorescent lights.

Upgrading parking lot lighting was a simple, quick, and cost-effective project for Westminster-Dubuque. Most churches probably have the same potential for savings while getting improved lighting.

Doug Cheever

January, 2022



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